Therefore, this patient's MI was subacute.
Now, what do you think the diagnosis is?
Posterior STEMI puts patients at risk of papillary muscle infarction and rupture. ( The posterior leaflet is supplied by posterior branches off the RCA and is vulnerable, whereas the anterior leaflet has its blood supply from the LAD and circumflex ) An infarct in the last several days or one week is consistent with acute papillary muscle rupture. This patient's presentation is classic for acute severe mitral regurgitation.1. Acute pulmonary edema2. Hyperdynamic heart (very low afterload out towards the left atrium and pulmonary veins3. Severe pulmonary edema without hypertension.4. Evidence of subacute inferoposterior MI ( most occur more than 24 hours from onset of MI )5. Absence of murmur because in acute rupture, the left atrium is small and as the LV contracts, the pressure between the LV and LA rapidly equalize so that there is no lengthy period of turbulence.
An echo with Doppler was the diagnostic study, and confirmed papillary muscle rupture. She was given immediate afterload reduction with nitroprusside, and taken for an angiogram which showed 2-vessel disease and a 90% RCA (the culprit) with flow. Balloon pump was placed and she was taken for immediate valve replacement and CABG and did well.
The initial troponin was 2.4 ng/ml (probably still elevated from the MI one week ago), but did rise to 19 ng/ml by the next morning. After CABG, it rose to 50 ng/ml.